Method for simultaneously producing fibers of different denier and similar crimp



June 12, 1962 G. HECHLER ETAL 3,038,779

METHOD FOR SIMULTANEOUSLY PRODUCING FIBERS OF DIFFERENT DENIER AND SIMILAR CRIMP Filed Aug. 5, 1959 F/GZ INVENTORS 2 Liz/Q4 ATTORNEY METHOD FOR SFMULTANEOUSLY PRODUCING F DEFFERENT DENiER AND SIMILAR Georg Hechler and Paul Weber, Siegburg, Germany, as-

signors to Phrix-Werke A.G., Hamburg, Germany Filed Aug. 3, 1959, Ser. No. 831,254 Claims priority, application Germany Aug. 6, 1958 4 Claims. (Cl. 18-54) This invention relates to a process for the production of fiber mixtures. More particularly, this invention is concerned with a method for producing mixtures of cellulosic filaments, fibers and threads having different denier size.

In spinning mills processing carded and worsted yarns, certain textile articles are made from mixtures of fibers having different weights as expressed in deniers. Depending upon the effect to be produced, the proportions of the fibers or filaments having different denier sizes are varied and fixed for each particular purpose. In order to produce yarns or fiber mixtures composed of fiibers of different denier size, the components are usually mixed in a suitable mixing apparatus, an operation which in many cases must be repeated several times to obtain a uniform mixture.

Fiber mixtures consisting of fibers of different weights are used in many fields of the textile industry. Thus, in the manufacture of rugs and carpets a certain floor effect or appearance is obtained by using a mixture consisting of 7, 14 and 22 denier fibers, the weight ratio of the three fiber components being about 30:40:30. Fiber mixtures composed of fibers of different weights are also employed for clothes, decorative fabrics and slivers.

In order to save the textile manufacturers the work of preparing fiber mixtures or yarns consisting of fibers of different weights, attempts have been made to produce such fiber mixtures or yarns directly fromv the raw material, thus transferring an operationheretofore practiced in spinning, combing and carding mills to the plant of the fiber manufacturer.

Thus, in accordance with a known process for making rayon staple fiber, a wool-type staple fiber having a varied staple length and being composed of fibers of different denier sizes is made by producing filaments of different weights from viscose fluid, forming these filaments into a continuous tow and then cutting the tow into definite lengths. These tows can be obtained by extruding the viscose fluid with the aid of a spinning machine equipped with spinnerets having different numbers of holes, the viscose being delivered to the spinnerets at the same speed (volume per minute).

It is also possible to obtain filaments of different denier sizes from spinnerets which all have the same number of holes, if the viscose fluid is delivered to the spinnerets with various speeds, using metering pumps of different output, or if the pressure under which the viscose fluid is extruded is varied, or if viscose fluids of different concentrations are fed to the spinnerets, or if the take-up in the setting bath is varied.

Of these possibilities, only the use of the spinnerets having different hole numbers is of practical importance because variations in pump output, extrusion pressure, viscose concentration and take-up complicate the execution of the process. To illustrate the use of spinnerets having different numbers of holes, a known process for making varied-size staple fiber utilizes a spinning machine having 30 nozzles with 300 holes, 30 nozzles with 450 holes, and 30 nozzles with 900 holes. All these nozzles are fed from the same viscose solution and the volume of solution delivered per minute as well as the take-up are the same for each nozzle. Using a delivery rate of 232 cc./m. and a take-up of 48 m./min., one obtains filaments of 18 deniers, 12 deniers and 6 deniers from a given viscose solution. The filaments are then formed into a tow, which may be stretched and cut into definite lengths. In this manner a wool-type staple fiber mixture consisting of fibers of different denier sizes can be obtained more easily than by mixing varied-size fibers in a particular carding or combing process.

However, fiber mixtures produced by the above-described prior art process, which involves the use of a spinning machine having spinnerets with different numbers of holes, are not entirely satisfactory. The variedsize fibers obtained in this manner are not uniform in regard to their textile properties. In particular, such fibers have different crimp.

This difference in properties is due to the fact that in the above-described process, the spinning conditions are the same for the fibers of different denier size. In order to obtain fibers of different weights which otherwise have the same textile properties, such as the same degree of waviness, it would be necessary to adapt the spinning conditions to the weight of the fiber. In other words, the composition of the setting bath as well as take-up and stretching would have to be adjusted to the fiber weights in order to form: fibers having different weights and yet certain equal properties. This is particularly true of the setting bath composition since a setting bath of a given composition will produce different effects, in particular, a different crimping effect, on low-denier size fibers, say, a 7 denier fiber, than on a high-denier size fiber, say a 22 denier fiber. It may thus be seen that the heretofore practiced method of making fibers of different weights cannot lead to the formation of fibers having the desired identical or similar textile properties.

It is therefore an object of the present invention to provide a process for the production of fiber mixtures composed of fibers of different weights which avoids the above-indicated disadvantages of the prior art method of making varied-weight fibers with the aid of one spinning machine.

Another object of the present invention is to provide a process for the production of fiber mixtures consisting of fibers of different denier size and yet similar textile properties.

A further object of the present invention is to provide a process for the production of fiber mixtures composed of fibers having different weights and. yet the same crimp.

Yet another object of the present invention is to provide a process for producing, with the aid of one spinning machine, mixtures of cellulosic filaments or fibers, in particular viscose rayon filaments or fibers, having different denier sizes and yet certain identical properties, such as crimp.

Still further objects will appear hereinafter.

With the above objects in view, the present invention provides a process for producing fiber mixtures containing fibers of different denier weights which comprises extiuding a fiber-forming solution through a plurality of spinnerets into a spinning bath, said spinnerets containing different numbers of minute holes through which said solution is extruded, the diameter of the holes contained in each spinneret being the larger, the smaller the number of the holes contained in said spinneret.

The present invention provides also an apparatus for spinning filaments by extruding a fiber-forming solution into a spinning batch, said apparatus comprising a plurality of spinnerets formed with minute holes through which said solution is extruded, the diameter of the holes contained in each spinneret being the larger, the smaller the number of holes contained in said spinneret.

The present invention is based on the surprising discovery that fibers having different denier weights and yet about the same crimp can be obtained by extruding a fiber-forming solution through spinnerets having different numbers of holes, if the diameter of these holes is adapted to the denier size of the fiber. In accordance with the present invention, the diameter of the holes is made the larger, the larger the denier size of the fibers extruded therethrough. Stated somewhat differently, the present invention provides a process for producing fiber-mixtures by extruding a fiber-forming solution through spinnerets having different numbers of holes wherein the holes of the spinnerets containing the lar-gest number of holes and giving the fibers of the smallest denier size have the smallest diameter and wherein the holes of the spinnerets containing the smallest number of holes and yielding the fibers of the greatest denier size have the largest diameter.

Due to the particular construction of the apparatus for this invention, the fibers or filaments of higher denier size are subjected to a higher stretch than the fibers or filaments of lower denier size because the stretch, which is determined by the ratio of the eflluence speed of the filmforming solution to the take-up speed of the first fiber takeup member, is proportional to the diameter of the holes of the spinnerets through which the solution is extruded.

It was of course entirely unobvious that the increase in hole diameter with rising denier size and the resultant increase in the stretch to which the fibers are subjected at the spinnerets, i.e. the adaptation of the take-up conditions to the denier size of the fiber as provided by the present invention, would lead to the formation of fiber mixtures in which the individual fibers of diflferent denier sizes have uniform textile properties, in particular nearly the same crimp or waviness, although all fibers originate from the same fiber-forming solution and are extruded into the same spinning bath. The fact that the fiber mixtures of this invention have uniform textile properties indicates that the different effects of take-up speed and stretching, which are identical for all fibers, are balanced in the process of this invention.

An embodiment of the apparatus of the present invention is, by way of example illustrated in the drawing in which:

FIG. 1 is a schematic side view of the apparatus of the present invention;

FIG. 2 are bottom views of types of spinnerets shown in FIG. 1 and drawn to an enlarged scale.

In the specific embodiment shown in the drawing, rayon rope 1 consisting of filaments of different denier sizes is made by extruding a viscose solution through a plurality of spinnerets 2, 3, 4, 5, 6 into an acid spinning bath 7, maintained in tank 8, supplying substantially the same volumes per unit of time of said viscose solution to all spinnerets by spinning pumps '9, 10, 11, 12, 13 and taking up by godets 14, 15, 16, 17, 18 the filaments formed with substantially the same speed at all spinnerets, the number of holes in said spinnerets being decreased from spinneret 2 to spinneret 7, while the width of the holes being increased respectively; and gathering the threads 19, 20, 21, 22, 23 thus obtained into a rope 1. This rope I is then wound around a godet unit 24, consisting of three reels 24a, b, running at a given speed and thereafter may be wound around a second godet unit 25, consisting of three reels 25a, b, 0 running at substantially higher speed so that the rope is stretched between the two godet units 24 and 25'. In accordance with procedures known in the fiber industry, such godets may be arranged in a secondary bath. The stretched rope may be cut into staples by means of a cutting device 26. The stapled fibres 27 being after treated and dried by manners known in the art showing a good crimp.

The number and the diameter of the holes contained in the spinnerets which are used in the practice of this invention are within the conventional ranges. Thus, the

4 number of holes may range from 10 to 3,000 or more per spinneret while the diameter of the holes may be within the range of 25.4 to 254 microns.

According to the present invention, the spinnerets having the largest number of holes contain the holes of smallest diameter and vice versa. Thus, a spinning machine in accordance with this invention may comprise two types of spinnerets, i.e. spinnerets with, say, 1,000- 3,000 holes, each of said holes having a diameter of, say, 150-60 microns, and spinnerets with, say. -l,000 holes, each of said holes having a diameter of, say, 350- microns.

It is also within the scope of this invention to use more than two types of spinnerets. Thus, in addition to the spinnerets with a large number of small holes and a small number of large holes, there may be present spinnerets having a medium number, say 500-1,500 of medium-sized, say 275-100 micron holes.

The number of the difierent type spinnerets contemplated by the present invention may also vary within wide limits. Thus, a spinning machine according to this invention may comprise a total of, say, 90 spinnerets, and this total number may be composed of equal amounts of the different spinneret types, say, 30 spinnerets with a large number of small holes, 30 spinnerets with a medium number of medium-sized holes, and 30 spinnerets with a small number of large holes. However, it is also within the purview of this invention to use different numbers of spinnerets of each type.

The process of this invention can be used to make ropes consisting of threads or groups of threads having different denier sizes, which may find application in the production of worsted yarns and coarse-spun. The process of the present invention is also applicable to the production of staple fiber mixtures composed of fibers of different denier sizes. In this application, the ratio of the amounts of the different denier size fibers may be varied so as to meet all specifications.

The following specific examples are given in further illustration of the invention.

Example 1 A viscose fluid having an alpha cellulose content of 9.0%, a CS content of 34.5-35.5 a viscosity'of 35-40 seconds and a H ripeness of 14.5-16.5 is extruded into a spinning bath containing 117-120 g./l. of sulfuric acid and 20-25 g./1. of zinc sulfate. The temperature is 48 50 C. and the density amounts to 1325-1535.

The spinning machine used in the experiment contains:

1200 hole/ 120 micron spinnerets 600 hole/ 180 micron spinnerets 400 hole/ 230 micron spinnerets The viscose fluid is delivered by the metering pumps at a rate of 312 cc./min. and the groups of filaments are combined into a rope, using a take-up speed of 24.0 m./min. at the first wheel. The take-up speed at the end is 39.6 m./min. so that the rope is stretched by 65%. Part of the stretching is effected at 85 C. in a secondary bath containing 70-80 g./1. sulfuric acid.

The stretched rope is cut under acid conditions. The staple fibers thus formed are aftertreated and dried as customary in the staple fiber industry. The fiber mixture obtained consists of 7.5, 15 and 22.5 denier size fibers.

Example 2 A viscose fluid characterized by an alpha cellulose content of 8.5-8.6%, an alkali ratio of 0.78, a CS; content of 34.5-35.5%, a viscosity of 40-43 seconds and a H ripeness of 14-15 is extruded into a spinning bath characterized by a sulftuic acid content of 112-115 g./l., a zinc sulfate content of 20-25 g./1., a temperature of 48- 50 C. and a density of 1.325-1.335, using the following types of spinnerets:

2x900 hole/ 120 micron (double headed nozzles) 900 hole/ 180 micron 600 hole/ 230 micron The viscose fluid is delivered by the metering pumps at a rate of 497 cc./min. and the take-up speed at the first wheel is 26.8 m./min. The take-up speed at the end amounts to 42.9 m./min. The rope is stretched by 60%, part of the stretching occurring at a temperature of 90-95' C. in a secondary bath containing 60-65 g./l. of sulfuric acid. The aftertreatment and the drying of the rope is efiected as usual in the rayon industry. The rope obtained consists of 7.5, 15, and 21.5 denier size filaments.

Example 3 A viscose fluid having the composition of the fluid described in Example 1 is extruded into a spinning bath of a composition as indicated in Example 1, using the following types of spinnerets: For

3.5 denier 2400 hole/ 85 micron. 7.0 denier 1200 hole/ 125 micron. 14.0 denier 600 hole/ 190 micron.

The viscose delivery rate amounts to 307 cc./ min. while the take-up at the end amounts to 42 m./min., the stretch being 65%.

The stretched rope thus obtained can be aftertreated and dried in known manner. Alternatively, it can be cut into staples under acid conditions and the staples can be aftertreated and dried by conventional procedures.

The following comparative data show the beneficial effects produced by the process of this invention.

Using a viscose fluid and a spinning bath of the compositions indicated in Example 1 but spinnerets of the following types.

400 hole/ 125 micron, 600 hole/ 125 micron, and 1200 hole/ 125 micron,

i.e. spinnerets having holes of equal diameter, there is obtained a fiber mixture consisting of 33% of 7 .3 denier fibers, 33% of 14.6 denier fibers, and 34% of 22 denier fibers.

The crimp of the dilferent denier size fibers thus formed, expressed in terms of the number of crimp arches per 100 mm. of wet staple fiber, is as follows:

, Arches 7.3 denier 16 14.6 denier 14 22.0 denier 4 This means that the dififerent denier size fibers have entirely different degrees of Waviness or crimp.

In contrast thereto, the crimp of the fibers contained in the fiber mixture of Example 1, where the holes in the spinnerets have the diameters indicated in Example 1, is as follows:

Arches 7.3 denier.. 16 14.6 denier 14 22.0 denier 12 7.3 denier 50-55 arches/100 mm. 14.6 denier 25-30 arches/100' mm. 22.0 denier -15 arches/100 mm.

In contrast thereto, the procedure of Example 1, where a spinning machine having spinnerets with holes of differ- 7.3 denier 50-55 arches/ mm. 14.6 denier 40-45 arches/100 mm. 22 denier 30-35 arches/ 100 mm.

The cutting of the ropes obtained by the process of this invention, which consists of threads of diflerent denier sizes, can be effected in such manner as to form staples of varied lengths. This can be accomplished by using different cutting machines, by cutting with knives arranged on a roll at different distances from one another, by employing knife rolls driven with dilferent speeds or by any other suitable means known per se. The production of staple fibers of different lengths can also be achieved by tearing.

Of course, it is also possible to produce staple fiber mixtures by cutting or tearing a rope consisting of threads of different denier sizes into pieces of the same length and mixing the staple fibers thus obtained with fiber pieces of diiferent lengths, the staple fibers of difierent lengths being either mixtures of fibers of different denier sizes or mixtures of fibers or" the same denier size.

While the invention has been described with reference to specific embodiments, it will be apparent to those skilled in the art that various modifications may be made and equivalents substituted therefor without departing from the principles and true nature of the present invention.

We claim:

1. In a method for simultaneously producing extruded fibers of diiferent denier and similar crimp characteristics, the steps of extruding a predetermined amount of fiberforming liquid so as to form a predetermined number of fibers of relatively small denier and having a predetermined total cross-sectional area; simultaneously extruding an equal amount of fiber-forming liquid so as to form a plurality of fibers of relatively large denier and having a total cross-sectional area greater than said predetermined total cross-sectional area, so that said fibers of relatively small denier will be extruded at a greater speed than said fibers of relatively large denier; and pulling and taking up all of the thus extruded fibers at substantially equal speed whereby said fibers of smaller denier Will be stretched less than said fibers of larger denier so that the crimp charaoteristcs of all of said fibers will be substantially similar.

2. In a method for simultaneously producing extruded fibers of difierent denier and similar crimp characteristics, the steps of extruding a predetermined amount of fiberforming liquid so as to form a predetermined number of fibers of relatively small denier and having a predetermined total cross-sectional area; simultaneously extruding an equal amount of fiber-forming liquid so as to form a plurality of fibers consisting of a lesser number than said predetermined number and of relatively large denier having a total cross-sectional area greater than said predetermined total cross-sectional area, so that said fibers of relatively small denier will be extruded at a greater speed than said fibers of relatively large denier; and pulling and taking up all of the thus extruded fibers at substantially equal speed whereby said fibers of smaller denier will be stretched less than said fibers of larger denier so that the crimp characteristics of all of said fibers will be substantially similar.

3. In a method for simultaneously producing extruded fibers of different denier and similar crimp characteristics, the steps of extruding a predetermined amount of viscose solution into an acid spinning bath so as to form a predetermined number of fibers of relatively small denier and having a predetermined total cross-sectional area; simultaneously extruding an equal amount of said viscose solution into said acid spinning bath so as to form a plurality of fibers consisting of a lesser number than said predetermned number and of relatively large denier having a total cross-sectional area greater than said predetermined total cross-sectional area, so that said fibers of relatively small denier will be extruded at a greater speed than said fibers of relatively large denier; pulling and taking up all of the thus extruded fibers at substantially equal speed whereby said fibers of smaller denier will be stretched less than said fibers of larger denier so that the crimp characteristics of all of said fibers will be substantially similar; and gathering the thus obtained fibers into a rope.

4. In a method of producing a composite fiber structure consisting of fibers of different denier and similar crimp characteristics, the steps of extruding at a greater speed fiber-forming liquid into fibers of relatively small denier simultaneously extruding at a lesser speed which is smaller than said greater speed fiber-forming liquid into fibers of relatively large denier so that said fibers of relatively small denier will be extruded at a greater speed than said fibers of relatively large denier extruded at a lesser speed; pulling and taking up at substantially equal speed said fibers of small denier extruded at a greater speed and said fibers of large denier extruded at a lesser speed and gathering them into a composite fiber structure whereby said fibers of smaller denier Wllll be stretched less than said fibers of larger denier so that the crimp characteristics of all of said fibers will be substantially similar; and gathering the thus obtained fibers into a composite fiber structure.

References (Iited in the file of this patent UNITED STATES PATENTS 1,883,347 Dreyfus et a1. Oct. 18, 1932 2,233,418 Kline Mar. 4, 1941 2,262,872 Whitehead Nov. 18, 1941 2,461,094 Taylor Feb. 8, 1949 2,673,368 Denyes Mar. 30, 1954 

1. IN A METHOD FOR SIMULTANEOUSLY PRODUCING EXTRUDED FIBERS OF DIFFERENT DENIER AND SIMILAR CRIMP CHARACTERISTICS, STHE STEPS OF EXTRUDING A PREDETERMINED AMOUNT OF FIBERFORMING LIQUID SO AS TO FORM A PREDETERMINED NUMBER OF FIBERS OF RELATIVELY SMALL DENIER AND HAVING A PREDETERMINED TOTAL CROSS-SECTIONAL AREA; SIMULTANEOUSLY EXTRUDING AN EQUAL AMOUNT OF FIBER-FORMING LIQUID SO AS TO FORM A PLURALITY OF FIBERS OF RELATIVELY LARGE DENIER AND HAVING A TOTAL CROSS-SECTIONAL AREA GREATER THAN SAID PREDETERMINED TOTAL CROSS-SECTIONAL AREA, SO THAT SAID FIBERS OF RELATIVELY SMALL DENIER WILL BE EXTRUDED AT A GREATER SPEED THAN SAID FIBERS OF RELATIVELY LARGE DENIER; AND PULLING AND TAKING UP ALL OF THE THUS EXTURDED FIBERS OF SUBSTANTIALLY EQUAL SPEED WHEREBY SAID FIBERS OF SMALLER DENIER WILL BE STRETCHED LESS THAN SAID FIBERS OF LARGER DENIER SO THAT THE LY SIMILAR. 